Toxic to humans, mercury is the only metallic element known to be liquid at standard Earth temperatures and pressures, so it poses a danger to children because it is so cold. However, many historical human activities include the use of mercury, including gold and silver mining, red cinnabar pigment production, felt production, and the manufacture of mechanical manometers, thermometers, and other instruments. One man even made a mercury fountain for the Spanish Pavilion at the 1937 World’s Fair in Paris, which is now on display at the Fundació Joan Miró in Barcelona.

Over the centuries, so much mercury has been used industrially that researchers have had a hard time explaining obsolete mercury because the element can stay in the environment almost indefinitely and pose a toxic hazard to humans and other life. Saul Guerrero and Larissa Schneider of the Australian National University produced a comprehensive historical dataset on the global mercury trade and production up to 1900. Their research has been published Proceedings of the National Academy of Sciences.

As primary sources, the authors examined records archived by governments, documents from local trade associations, cargoes on ships reported in newspapers, and other sources. They compiled market data for mercury equivalent to the net import/export balance for each country, including the share of domestically produced and non-exported mercury. The researchers compiled all of this data in what they call a “mercury resource pool” that accounts for the total historical anthropogenic mercury inside and outside the global mercury biogeochemical cycle. The authors say the result is a chronological and regional report with unprecedented detail that puts limits on the ecological magnitude of ancient mercury.

The use of mercury evolved from 1500 to 1900, from the monopoly of silver producers in the New World to a vast global market that included the Western world, China, and India. The authors note that before 1900, significant quantities of anthropogenic mercury were removed from the global biogeochemical mercury cycle either by chemical sequestration in industrial products such as felt and cinnabar, or as an industrial byproduct in the form of calomel, a solid mercuric chloride mineral. embedded in the mineral matrix.

China alone accounted for 20% of the global mercury market, both as a consumer and exporter, in the 19th century, meaning that “significant amounts of mercury … were chemically absorbed as cinnabar and would therefore not be part of the global biogeochemical production of mercury.” The authors argue that the gold rush, previously thought to be the main cause of anthropogenic mercury deposits, did not make up a significant percentage, referring to the surprisingly low mercury use by Australian gold prospectors.

“While chemically absorbed mercury played an important role in the anthropogenic mercury mass balance before 1900, this explains the lack of supporting evidence in the natural archive for large mercury emission pulses in the late 19th century,” they write.

They argue that previous re-estimations of mercury emissions from gold and silver mining did not take into account the absorption of mercury in the form of calomel and combined the different gold and silver mining processes. Additionally, previous models did not account for significant exports from California and China.

The authors note that future more accurate studies will require data on all alternative global mercury hotspots not associated with precious metal mining, and a better-documented historical assessment of mercury losses at manufacturing facilities. Source